Can't decide what class I'd like most to reroll as, there's two I'm enjoying. So I figured I'd ask endgame people on the server, of these, which do groups tend to be lacking for endgame PVE:

Sniper

Guardian DPS

I would guess vigilance guardians aren't that popular or much wanted for endgame since sentinels seem to over shadow them... I really like Sniper a lot, but I don't like playing on the Empire side, and I'm not overly fond of the Smuggler style, I'd much prefer the covert secret agent.

If you're talking strictly DPS for PVE, Sniper/Gunslinger is the way to go out of the two choices.

Ranged DPS is always a solid choice. The only downside to it is that you're only going to be DPS'ing with him. With the Guardian you can DPS and also get gear to tank.

The general rule of thumb is to pick something you are going enjoy. I love playing Lethality spec on my sniper....but part of the reason for that is because I love topping the DPS charts with it. I like my Sorc for dps and the fact i can switch to healer if needed and it's still fun to play.

If you don't have any interest in tanking, I would recommend Marauder to you if you want a melee dps class.

Merc is always a great choice too. Great heals and DPS with the ability to move around a lot.

GScheff made some excellent points and I agree: you got to play a class you find fun. Don't try and pick a class based on how useful other people on these forums perceive them to be.

The biggest decision you need to make is that of class perference. Do you exclusively enjoy dps? If so you want to consider marauders and snipers as they have some of the best dps period. The down side is, you can only dps as neither marauders or snipers have a healing or tank tree. If tanking or healing is something you may want to do, consider juggs, powertech (tanks or dps) or operatives, mercs (healing).

I don't have a lot of experience with sorcs but they have both a melee tank/dps tree and a ranged healer/dps tree.

Good luck!